Get a AC guy to clean. Are you in Klang Valley? That's why now I go for air purifying AC with ionizer that cleans the internals (clean mode, mould proof operation, auto clean depending on manufacturer and model) as they will kill the mould inside.

AC air is drier but AC pipes at the fins will sweat due to higher indoor humidity whilst in operation. Mould growth cannot be avoided. I've seen or heard of it in all AC that's not been serviced.

I would have thought this is general phenomenon unless an old technique is being overlooked to deal with this apart from blower unit cleaning?

I don't have such problem. There is only dirt at that blower side.

Room humid during aircon is 40-45%.

New type aircon normally have antimold treated on the fin, water tray or some parts.

The air blowing out is dry. So shouldn't be mold grow on it. Unless at the water tray below the fin.

Dry mode basically dries the air. The AC will still sweat at the heat exchanger except that the air produced is mildly drier than before but temperature may not drop as much. Basic dehumidifier function.

Get a hygrometer from Ace hardware or Homefix sells Stadler Form Selina. This will read your room's humidity. Some wall clocks like Seiko or Citizen have thermometer and hygrometer built in feature.

You can buy at ACE or Caring, watson etc.

I have the sharp air purifier which have humid reading. So I can see my room humid.

Indoor Humidity at 80%RH at 24°C (Cameron) is nice but at 80%RH at 28°C (e.g. bathroom) it's very stuffy already..worse even at 29°C onwards. Tiles will repel hence, the place will stay damp or humid vs marble which will absorb it.

Old AC without inverter has a very straightforward program that dehumidifiy and lowers temperature but beware of long term health effects as the lungs can dry out. Old folks and young children health will be a concern.

Newer AC inverters have a human comfort level that keeps it at a comfortable humidity-temperature range. 45-65% is comfortable but 60-65% is not too drying healthwise which I sense is optimum. But different ppl have different preference. Some like it colder which is because it's too warm in the day or even the night due to room configuration (evening sun) or just used to this feeling.

What tricks the mind to perceive comfort is moving air. Ceiling fan is the great helper here. If you can get the AC to blow towards the ceiling fan e.g. Coanda effect, the added windchill should allow setting the AC higher like 25-28°C depending. Or even dry mode.

Kitchen should be colder as esp where cooking is done.

Should be good enough.

If you want to hang or put on the table, get a nicely look la.

table type
http://www.lazada.com.my/sh-high-precision...05109.html?ff=1

hang type
http://www.lazada.com.my/lcd-digital-therm...68773.html?ff=1

Mentioned before...up to personal preference. Mine is between 60-65%RH at 27°C.

From time to time spray some 3% hydrogen peroxide on it. H2O2 is safe and non toxic and it kills mold and mildew effectively.

Pharmacy got sell in small bottle but it is not cost effective for general cleaning.
I bought a 500ml 35% h202 for RM50. More cost effective if dilute with distilled water.
To get the 3% h2o2, dilute 1 part 35% to 11 part distilled water. Keep the 3% h2o2 in used spray bottle.
Distilled water can get AEON brand. 90sen for 1500ml bottle.

You can use this --> https://www.tilex.com/tilex-bathroom-cleaning-products/

I use it on my bathroom.

Can get it from ACE.

Your AC got special mold ?

This spray is deal with mold.

Spray, rub and rinse.

Easy way, get a service.

If complicated, forget about the 35% hydrogen peroxide and the dilution.
Just go pharmacy buy the ready to use 3% or 6% in small bottle. Around Rm6+. Can also be used for standby first aid for minor cuts and bruises.

Add on:
Oh ya, hydrogen peroxide in low concentrations (3% or 6% ) is definitely friendly to your aircon.if it can apply to human, aircond lagi no problem. After all, it is water with extra oxygen atom.

Thanks for tip    , very good product and definitely the foam dissolves the dust inside the cooling coil. Recommended for anyone who wants DIY clean their indoor unit cooling coil 

30ml too little, should buy at least 100ml. Because you need to put into a sprayer.
Anyway, mix the 30ml 6% HP with equal amount of distilled water in a used spray bottle. Then spray your ac.
I have 500ml 35% h2o2, can make a lot of 3% h2o2. if you need more hp, I can share it with you.

Below is picture of 3% hp in a spray bottle.
[attachmentid=8680304]

Just leave it dry. Use the finest mist sprayer possible.

I'm going to clean 3 a/conds this weekend.
Managed to find and buy a few Silver-ion filter clothes at Daiso for RM5.90 a packet.